A statistical and spatial analysis of chemical contaminants in Cocos Lagoon, Guam

Abstract

Cocos Lagoon is located on the southwestern end of the coast of Guam, and contains extensive coral reefs and an array of fish species. Within the Lagoon is a former US Coast Guard LORAN station on Cocos Island. Hazardous materials appear to have been disposed of on land and in near shore waters during the operation of the LORAN station, between the years of 1944 and 1963, exposing surrounding waters, sediment, fish species and humans to these materials. As part of a project to quantify chemical contaminants in Cocos Lagoon, and to address local and agency human health concerns, approximately 190 chemical contaminants were analyzed in sediments from 25 sites, along with 27 fish tissue samples from 16 sites. Higher levels of chemical contaminants were found in fish tissues collected from around Cocos Island, the site of the former LORAN station. Concentrations of polychlorinated biphenyls (PCBs), for example, were above an EPA recreational fishers’ screening value (SV) in some fish species from around Cocos Island, indicating risk to humans consuming fish from this area. PCBs at high concentrations are known to cause negative effects on resident marine aquatic organisms and human health concerns include cancer. Characterizing contaminant impacts to aquatic marine organisms and possible human health results from this project will provide resource managers with key information needed to make effective decisions for the health of Cocos Lagoon and also gauge the efficacy of restoration activities. The results show high levels of PCBs in the fish species from Coco Lagoon. This indicates that there is a high risk of adverse health effects such as cancer if consumed by humans.